HackerRank_ElectronicsShop

//Electronics Shop
#include <iostream>
using namespace std;
int main()
{
    long long int b, key, usb, k[900001], u[900001], sum, max=-2;
    cin >> b >> key >> usb;
    for(long long int i=0;i<key;i++)
    {
        cin >> k[i];
    }
    for(long long int y=0;y<usb;y++)
    {
        cin >> u[y];
    }
    for(long long int i=0;i<key;i++)
    {
        for(long long int y=0;y<usb;y++)
        {
            sum = k[i]+u[y];
            if(sum<b && sum > max){max=sum;}
        }
    }
    if(max==-2){cout<<"-1";}
    else{cout << max;}
    return 0;
}