题解 | 小红取数

#include<iostream>
#include <vector>
using namespace std;
using ll =long long; 
int main(){
    ll n;
    cin>>n;
    vector<ll>a(n);
    ll jis=0;
    ll ous=0;
    for(ll i =0;i<n;i++){
        cin>>a[i];
        if(a[i]&1)jis++;
        else ous++;
    }
    if(jis==0){
        cout<<"-1";
        return 0;
    }
   else cout<<jis;
    return 0;
}