11. Cacey and Calphabet

#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;

#define MAXN 51

int main()
{
    char s[MAXN]; int dp[MAXN];
    for (int i = 0; i < MAXN; i++) dp[i] = 1;
    scanf("%s", s);
    int len = strlen(s), lis_len = 1, res;
    for (int i = 1; i < len; i++) {
        for (int j = 0; j < i; j++) {
            dp[i] = s[i] > s[j] ? max(dp[j] + 1, dp[i]) : dp[i];
            lis_len = max(lis_len, dp[i]);
        }
    }
    res = 26 - lis_len;
    printf("%d", res);
    return 0;
}