C :

#include <stdio.h>
#include <stdlib.h>
int main()
{
	printf("5\n");
	return 0;
}
//Author: ITProgrammer

C++ :

#include<bits/stdc++.h> 
using namespace std; 

int main(){ 
	int i = 5;
	long long s = 0;
	int c = 0;
	while(1==1){
		s=pow(2,pow(2,i));
		for(int j = 2;j <= sqrt(s);j++){
			if(s % j == 0){
				c++;
				break;
			}
		}
		if(c != 0){
			cout<<i;
			break;	
		}
		i++;
	}
	return 0;
} 

Python :

import math
import sys
# x,y=list(map(int,input().split()))
# n=int(input())
def zs(n):
    if n==1:
        return 0
    elif n==2:
        return 1
    else:
        for i in range(2,int(n**0.5)+1):
            if n%i ==0:
                return 0
        return 1
def hs(i):
    return pow(2,pow(2,i))+1
i=0
while zs(hs(i))==1:
    i=i+1
print(i)