#include <bits/stdc++.h> using namespace std; int main() { int a[12]= {31,28,31,30,31,30,31,31,30,31,30,31}; int n,week=4,cnt=0; cin >> n; for(int k = 1998; k<=n; k++) { if(k%4==0&&k%100!=0 || k%400==0) { a[1] = 29; } else { a[1] = 28; } for(int i = 0; i<12; i++) { for(int j = 1; j<=a[i]; j++) { if(week==5 && j == 13 && k == n) { cnt++; } week = (week+1)%7; } } } cout << cnt; return 0; }