#include<stdio.h>

#define INPUT "stergeri.in"
#define OUTPUT "stergeri.out"
#define NMAX 100001

FILE *fin = fopen(INPUT, "r"), *fout = fopen(OUTPUT, "w");

long N, M, K;
long A[ NMAX ], B[ NMAX ];

void readData()
{
  fscanf(fin, "%ld %ld %ld", &N, &M, &K);

  for(long i = 0; i < M; ++i)
    fscanf(fin, "%ld %ld", A+i, B+i);
}

void solve()
{
  for(long i = M-1; i >= 0; --i)
    if(A[ i ] <= K)
      K += (B[ i ] - A[ i ] + 1);

  fprintf(fout, "%ld\n", K);
}

int main()
{
  readData();

  solve();

  fclose(fin);
  fclose(fout);

  return 0;
}