#include<stdio.h>
#define dim 2000000001
using namespace std;

bool a[dim];

 int main()
 { long long n,m,k,i,x,y,co,j;
	 
	 FILE *f = fopen("stergeri.in", "r");
	 FILE *g = fopen("stergeri.out", "w");
	
	 fscanf(f, "%lld%lld%lld", &n, &m, &k);
	 
	 for(i = 1; i <= m; i ++)
		 {
			 fscanf(f, "%lld%lld", &x, &y);
			 co = 0; j = 1;
			 while (co <= y)
				{
					if(co < x && a[j] == 0) co++;
						else if((co >= x) && (a[j] == 0)) a[j-1] = 1, co++;
					j++;
				}
		 }
	 
	 co = 0; i = 1;
		 while(co <= k)
			 {if(a[i] == 0) co++;
			  i++;
			 } 
			 
	 fprintf(g, "%lld\n", i-1);
	 
	 fclose(f);
	 fclose(g);
	 return 0;
 }