#include<stdio.h>
using namespace std;
 
int main() {
    int n = 0, k = 0;
 
    scanf("%i", &n);
    scanf("%i", &k);
 
    int xTotal = 0;
 
    for (int i = 0; i < n; i++) {
        // initalize left and right for this segment
        int l, r;
        scanf("%i", &l);
        scanf("%i", &r);
 
        int x = (r-l)+1; // calculate how many nums are (x) (the value of this current set)
        xTotal+=x;
    }
 
    // find the nearest number divisible by k
 
    int currentNumber = xTotal;
    while (currentNumber%k != 0) {
        currentNumber++; // only increment since the only moves we can do is increase (l-1, r+1)
    }
 
    printf("%i", currentNumber-xTotal);
 
    return 0;
}

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MiAzCjEgMgozIDQK

2 3
1 2
3 4