C :

#include<stdio.h>
int main()
{
	int i,n,c=0;
	scanf("%d",&n);
	for(i=1900;i<=n;i++)
	{
		if((i%4==0&&i%100!=0)||(i%400==0)) c++;
	}
	printf("%d",c);
	return 0;
}

C++ :

#include <iostream>
using namespace std;

int main(){
	int i,n,c = 0;
	cin>>n;
	for(i = 1900;i <= n;i++){
		if(i%4==0&&i%100!=0 || i % 400==0){
//			cout<<i<<endl;
			c++;
		}
	}
	cout<<c;
}

Java :

import java.util.Scanner;

public class Main{

public static void main(String[] agrs){

Scanner sc = new Scanner(System.in);
int n = sc.nextInt();
int s = 0;
for(int i = 1900;i <= n;i++){
		
		if((i % 4 == 0 && i % 100 != 0) || (i % 400 == 0)){
		s++;
		}
}System.out.println(s);
}
}

Python :

n = int(input())
x = 0
for i in range(1900, n + 1):
    if((i % 4 == 0) and (i % 100 != 0)) or (i % 400 == 0):
        x += 1
print(x)