Problem:
Score : 100 points

Problem Statement

We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.

How many grams of sand will the upper bulb contains after t seconds?

Constraints

1≤X≤10^9

1≤t≤10^9

X and t are integers.

Input

The input is given from Standard Input in the following format:

X t

Output

Print the number of sand in the upper bulb after t second.

Sample Input 1

100 17

Sample Output 1

83

17 out of the initial 100 grams of sand will be consumed, resulting in 83 grams.

Sample Input 2

48 58

Sample Output 2

0

All 48 grams of sand will be gone, resulting in 0 grams.

Sample Input 3

1000000000 1000000000

Sample Output 3

0

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
#define rep(i,a,b) for(ll i=ll(a);i<ll(b);i++)
#define irep(i,a,b) for(ll i=ll(a);i>=ll(b);i--)
#define pb push_back
#define mp make_pair
#define pll pair<ll,ll>
#define endl "\n"
using ll=long long;
using ld=long double;
using namespace std;
ll mod= 1e9+7;
ll GCD(ll a, ll b) { return b ? GCD(b, a%b) : a; }

ll c[100][100];
main(){
    ll x,t,n,m,k,tmp=0,ans=0;
    cin>>x>>t;
    cout<<max(x-t,(ll)0);
}