#include <stdio.h>
int main() {
	long long n,m,k,s = 0,x,y,min = 2000000000;

	FILE*in  = fopen("stergeri.in","r");
	FILE*out = fopen("stergeri.out","w");

	fscanf(in, "%lld", &n);
	fscanf(in, "%lld", &m);
	fscanf(in, "%lld", &k);

	
	for (;m;m--) {
	    fscanf(in, "%lld%lld", &x, &y);
	    if (x < min) min = x;
	    s += y-x+1;
	}
	if (k < min)
 	   fprintf(out,"%lld\n", k);
	else	
		fprintf(out, "%lld\n", s+k);
	return 0;
}