#include <bits/stdc++.h> using namespace std; bool isrich(int x){ if(((x %4 == 0) && (x % 100 != 0)) || x % 400 == 0){ return true; } return false; } int main(){ int y, m, d; cin >> y >> m >> d; bool flag = isrich(y); vector<int> vec = {0, 31, 28, 31, 30, 31, 30...