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<bits/stdc++.h>
using namespace std;
 
template <class T1, class T2>
ostream& operator << (ostream& out, const pair <T1, T2> p)
{
	out << '(' << p.first << ',' << p.second << ')';
	return out;
}
 
template <class T1, class T2>
istream& operator >> (istream& in, pair<T1, T2> &p)
{
	in >> p.first >> p.second;
	return in;
}
 
template <class T>
istream& operator >> (istream& in, vector<T> &v)
{
	for (T &x : v)
		in >> x;
	return in;
}
 
template <class T>
ostream& operator << (ostream& out, const vector<vector<T> > &v)
{
	for (const vector<T> &x : v)
		out << x << '\n';
	return out;
}
 
template <class T>
ostream& operator << (ostream& out, const vector<T> &v)
{
	for (const T &x : v)
		out << x << ' ';
	return out;
}
 
 
#define ll long long
#define lf long double
#define pb push_back
#define mp make_pair
#define F first
#define S second
typedef pair <ll,ll > ii;
typedef vector <ll> vi;
typedef vector <ii> vii;
typedef vector <bool> vb;
typedef vector <vector <ll> > vv;
typedef vector <vector <vector<ll> > > vvv;
typedef vector <string> vs;
typedef vector <lf> vf;
#define sz(x) (ll)(x).size()
#define tr1(x) cerr << #x << ": " << x << nl
#define tr2(x, y) cerr << #x << ": " << x << " | " << #y << ": " << y << nl
#define tr3(x,y,z) cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<nl
#define tr4(x,y,z,w) cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<" | "<<#w<<": "<<w<<nl
#define trv(a) cerr<<#a<<": ";for(ll zz=0;zz<sz(a);zz++) cerr<<a[zz]<<" ";cerr<<nl
#define trset(s) cerr<<#s<<": ";for(auto &i:s) cerr<<i<<" ";cerr<<nl
#define epsilon 0.000000001L
#define inf 9999999999999999ll// ~ 10^16
#define nl endl
#define all(x) x.begin(), x.end()
#define r_all(x) x.rbegin(), x.rend()
#define fast()  ios_base::sync_with_stdio(false);cin.tie(NULL)
#define mod 1000000007ll
#define modulo 998244353ll
ll power(ll a,ll b){return b?power(a*a%mod,b/2)*(b%2?a:1)%mod:1;}

int main()
{
    fast();
    vi a(5);
    cin>>a;
    for(ll i=0;i<5;i++)
    {
        if(a[i]==0)
        {
            cout<<i+1<<nl;
        }
    }
}