50分只有输出Lucky Word的错了

#include<bits/stdc++.h>
using namespace std;
int f(int n){
    for(int i=2;i<n;i++)
        if(n%i==0)return 0;
    return 1;
}
int main(){
    string s;
    cin>>s;
    int a[30];
    for(int i=0;i<s.size();i++)
        a[s[i]-97]++;
    int maxn=114514,minn=-114514;
    for(int i=0;i<26;i++){
        if(a[i]<minn&&a[i]!=0)minn=a[i];
        if(a[i]>maxn)maxn=a[i];
    }
    if(f(maxn-minn)){
        cout<<"Lucky Word"<<endl;
        cout<<maxn-minn<<endl;
        return 0;
    }
    cout<<"No Answer"<<endl;
    cout<<0<<endl;
    return 0;
}