#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#define N 110using namespace std;struct Fruit{	int a,b;};Fruit num[N];int c1[N],c2[N];int main(){	int n,m;	while(scanf("%d%d",&n,&m)!=EOF){		for(int i=1;i<=n;i++)		scanf("%d%d",&num[i].a,&num[i].b);		memset(c1,0,sizeof(c1));		memset(c2,0,sizeof(c2));		for(int i=num[1].a;i<=num[1].b;i++)		c1[i]=1;		for(int i=2;i<=n;i++){			for(int j=0;j<N;j++){				for(int k=num[i].a;k<=num[i].b&&k+j<N;k++)				c2[k+j]+=c1[j];			}			for(int j=0;j<N;j++)			c1[j]=c2[j],c2[j]=0;		}		printf("%d\n",c1[m]);	}	return 0;}