Ural_1494. Monobilliards(栈)

#include <iostream>
#include <cstdio>

using namespace std;

const int N = 100007;

int st1
, st2
;

int main() {
//freopen("data.in", "r", stdin);

int i, top1, top2, n;
while(cin >> n) {
for(i = 0; i < n; i++) {
cin >> st2[i];
}
top1 = 0; top2 = 0;
for(i = 1; i <= n; i++) {
st1[++top1] = i;
while(top1 != 0 && st1[top1] == st2[top2]) {
--top1; ++top2;
}
}
if(top1)    cout << "Cheater";
else    cout << "Not a proof";
cout << endl;
}
return 0;
}