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

int main(){
  int n,m,k;
  long int sum;
  scanf("%d%d%d",&n,&m,&k);
  int l[m],r[m];
  for(int i=0;i<m;i++) scanf("%d%d",&l[i],&r[i]);
  long int *p,*pp,*temp;
  p = malloc(sizeof(long int)*n);
  pp = malloc(sizeof(long int)*n);
  for(int i=0;i<n;i++) p[i]=0;
  p[0]=1;
  for(int i=0;i<k;i++){
    temp=p;p=pp;pp=temp;
    for(int j=0;j<n;j++)p[j]=0;
    for(int j=1;j<n;j++)pp[j]+=pp[j-1];
    for(int j=0;j<m;j++){
      sum=pp[r[j]-1]-(l[j]>1?pp[l[j]-2]:0);
      p[l[j]-1]+=sum;
      if(r[j]<n)p[r[j]]-=sum;
    }
    for(int j=1;j<n;j++)p[j]+=p[j-1];
    for(int j=0;j<n;j++)p[j]%=1000000007;
  }
  printf("%d\n",p[n-1]);
  free(p);
  free(pp);
  return 0;
}