学步园

#include <cstdio>
#include <cstring>
char tab[111][111];
bool ok[111];

int main() {
    int n, m;
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; i++)
        scanf("%s", &tab[i]);

    int cnt = 0;
    for (int i = 0; i < m; i++) ok[i] = 1;

    for (int i = 0; i < m; i++) {
        for (int j = 1; j < n; j++) {

            if (tab[j][i] < tab[j-1][i]) {
                bool add = true;

                for (int k = 0; k < i; k++) {
                    if (ok[k] == 1 && tab[j-1][k] < tab[j][k])
                        add = false;
                }
                if (add) { cnt++; ok [i] = 0; break;}
            }
        }
    }
    printf("%d\n", cnt);
    return 0;
}