#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#define inf 0x7fffffff
#define T 10000
using namespace std;
inline int read(){
int x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
struct edge{int to,next,v;}e[200001];
int n,cnt=1,s,ans,head[10001],h[10001];
inline void ins(int u,int v,int w){
<span style="white-space:pre"> </span>e[++cnt]=(edge){v,head[u],w};head[u]=cnt;
<span style="white-space:pre"> </span>e[++cnt]=(edge){u,head[v],0};head[v]=cnt;
}
inline bool bfs(){
<span style="white-space:pre"> </span>int t=0,w=0,now,q[20001];
<span style="white-space:pre"> </span>memset(h,-1,sizeof(h));
<span style="white-space:pre"> </span>h[0]=q[0]=0;
<span style="white-space:pre"> </span>while(t<=w){
<span style="white-space:pre"> </span>now=q[t++];
<span style="white-space:pre"> </span>for(int i=head[now];i;i=e[i].next){
<span style="white-space:pre"> </span>if(e[i].v&&h[e[i].to]==-1){
<span style="white-space:pre"> </span>h[e[i].to]=h[now]+1;
<span style="white-space:pre"> </span>q[++w]=e[i].to;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>if(h[T]==-1)return 0;
<span style="white-space:pre"> </span>else return 1;
}
inline int dfs(int x,int f){
<span style="white-space:pre"> </span>if(x==T)return f;
<span style="white-space:pre"> </span>int used=0,rest;
<span style="white-space:pre"> </span>for(int i=head[x];i;i=e[i].next){
<span style="white-space:pre"> </span>if(e[i].v&&h[e[i].to]==h[x]+1){
<span style="white-space:pre"> </span>rest=f-used;
<span style="white-space:pre"> </span>rest=dfs(e[i].to,min(e[i].v,rest));
<span style="white-space:pre"> </span>e[i].v-=rest;
<span style="white-space:pre"> </span>e[i^1].v+=rest;
<span style="white-space:pre"> </span>used+=rest;
<span style="white-space:pre"> </span>if(used==f)return f;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>if(!used)h[x]=-1;
<span style="white-space:pre"> </span>return used;
}
int main(){
<span style="white-space:pre"> </span>freopen("balla.in","r",stdin);
<span style="white-space:pre"> </span>freopen("balla.out","w",stdout);
<span style="white-space:pre"> </span>n=read();
<span style="white-space:pre"> </span>while(1){
<span style="white-space:pre"> </span>ans++,s++;
<span style="white-space:pre"> </span>for(int i=1;i<s;i++)
<span style="white-space:pre"> </span>if(sqrt(i+s)==(int)(sqrt(i+s)))
<span style="white-space:pre"> </span>ins(i,s+5000,1);
<span style="white-space:pre"> </span>ins(0,s,1);ins(s+5000,T,1);
<span style="white-space:pre"> </span>while(bfs())ans-=dfs(0,inf);
<span style="white-space:pre"> </span>if(ans>n)break;
<span style="white-space:pre"> </span>}
<span style="white-space:pre"> </span>printf("%d\n",s-1);
<span style="white-space:pre"> </span>return 0;
}