Filling Jars

Animesh has N empty candy jars numbered from 1 to N with infinite capacity. He performs M operations. Each operation is described by 3 integers a, b and k where a and b are index of the jars and k is the number of candies to be added inside each jar with index between a and b (both inclusive). Can you tell the average number of candies after M operations?

Input Format
The first line contains two integers N and M separated by a single space.
M lines follow. Each of the M lines contain three integers a, b and k separated by single space.

Output Format
A single line containing the average number of candies across N jars, rounded down to the nearest integer.

Constraints
3 <= N <= 107
1 <= M <= 105
1 <= a <= b <= N
0 <= k <= 106

Sample Input #00

5 3
1 2 100
2 5 100
3 4 100

Sample Output #00

160

Explanation
Initially each of the jar contains 0 candies

0 0 0 0 0  

First operation

100 100 0 0 0  

Second operation

100 200 100 100 100  

Third operation

100 200 200 200 100  

Total = 800, Average = 800/5 = 160

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    int i,j;
    long int N,M,a,b,k,sum=0,c;
    scanf("%ld %ld",&N,&M);
    
    for(i=1;i<=M;i++)
    {
      scanf("%ld %ld %ld",&a,&b,&k);
     c=b-a+1;
     c=c*k;
     sum=sum+c;        
    }
    sum/=N;
    printf("%ld",sum);    
    return 0;
}