#include<stdio.h>
FILE *f=fopen("stergeri.in","r");
FILE *g=fopen("stergeri.out","w");

long long n,m,k,min,x,a,b;

int main()
{

fscanf(f,"%lld%lld%lld",&n,&m,&k);
 
 fscanf(f,"%lld%lld",&a,&b);
   x+=b-a+1;
 min=a;
 for(long i=2;i<=m;i++)
  { fscanf(f,"%lld%lld",&a,&b);
   x+=b-a+1;
        if(min>a)
     min=a;
   } 

 if(min<k)
    fprintf(g,"%lld",x+k);
   else fprintf(g,"%lld",k);
fcloseall();

return 0;

}