Problem:
Score : 100 points

Problem Statement

We have five variables x_1, x_2, x_3, x_4, and x_5.

The variable x_i was initially assigned a value of i.

Snuke chose one of these variables and assigned it 0.

You are given the values of the five variables after this assignment.

Find out which variable Snuke assigned 0.

Constraints

The values of x_1, x_2, x_3, x_4, and x_5 given as input are a possible outcome of the assignment by Snuke.

Input

Input is given from Standard Input in the following format:

x_1 x_2 x_3 x_4 x_5

Output

If the variable Snuke assigned 0 was x_i, print the integer i.

Sample Input 1

0 2 3 4 5

Sample Output 1

1

In this case, Snuke assigned 0 to x_1, so we should print 1.

Sample Input 2

1 2 0 4 5

Sample Output 2

3

Solution in C++ (GCC 9.2.1) (judge verdict: Accepted)

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
 
using namespace __gnu_pbds;
using namespace std;

#define double      	long double
#define int         	long long
#define pb          	push_back
#define pii         	pair<int,int>
#define vi          	vector<int>
#define vii         	vector<pii>
#define mi          	map<int,int>
#define mii         	map<pii,int>
#define all(a)      	(a).begin(),(a).end()
#define sz(x)       	(int)x.size()
#define endl        	"\n"
#define repp(i,a,b) 	for(int i=a;i<b;i++)
#define rep(i,a,b) 		for(int i=a;i<=b;i++)
#define brep(i,a,b)     for(int i=a;i>=b;i--)
#define deb1(x)      	cout << #x << "=" << x << endl
#define deb2(x, y)  	cout << #x << "=" << x << "," << #y << "=" << y << endl
#define deb3(x, y, z)  	cout << #x << "=" << x << "," << #y << "=" << y << "," << #z << "=" << z << endl
#define trace(v) 		for(auto it=v.begin();it!=v.end();it++)cout<<*it<<" ";cout<<endl;
#define tracearr(a,l,r) for(int iii=l;iii<=r;iii++)cout << a[iii] << " ";cout << endl;
#define PI          	3.1415926535897932384626
#define F 				first
#define S 				second
#define clr(x) 			memset(x, 0, sizeof(x))
#define IOS         	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);


typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
// *s.find_by_order(1) - gives the 2nd samllest element in set
// s.order_of_key(x)   - gives the number of elements in the set which are strictly smaller than x


const int N=1e5 + 5;
const int MOD=1e9 + 7;

int32_t main()
{
	IOS;
	int T=1;

	// int numOfSetBits = __builtin_popcountll(n);
	std::cout << std::fixed << std::setprecision(12);
	while(T--)
	{
		int a[10];
		rep(i,1,5)
		{
			cin >> a[i];
		}
		rep(i,1,5)
		{
			if(a[i]==0)
			{
				cout << i;
				return 0;
			}
		}
	}
}