#include #include using namespace std; //#define DISABLE_PRINT #if defined(ENABLE_PRINT) && !defined(DISABLE_PRINT) #define P(...) fprintf(stderr, __VA_ARGS__) #define P2(fmt) fprintf(stderr, fmt) #define LP fprintf(stderr, "L: %d\n", __LINE__) #else #define P(...) ((void)0) #define P2(fmt) ((void)0) #define LP ((void)0) #endif #define rep(i, n) for(int i = 0; i < (int)(n); ++i) #define ALL(x) x.begin(),x.end() using ll = long long; using ull = unsigned long long; int main(int, const char**) { int N; cin >> N; string S; cin >> S; vector nexts(N + 1); rep(i, N) nexts[i] = i + 1; auto check = [&](int i) { assert(i < N); if(S[i] == 'A' || S[i] == 'G' || S[i] == 'C' || S[i] == 'T') return true; return false; }; int c = -1; rep(i, N) { if(check(i)) c = i; } cout << c + 1 << endl; return 0; }