#include <stdio.h>

int main() {
    FILE* f = fopen("energii.in.txt","r");
    if(f == NULL)
        puts("Fisierul energii.in nu s-a putut decshide");
    int G,W;
    fscanf(f,"%d", &G);
    fscanf(f,"%d", &W);
    int E[G],C[G];
    int e,c;
   for(int i=0;i<G;i++){
       fscanf(f,"%d%d", &E[i], &C[i]);
    }
    int min = 10001;
    for(int i=0;i<G;i++){
        if(E[i] >= W)
            if(C[i]<min)
                min = C[i];
    }
    FILE* fo = fopen("energii.out.txt","w");
    if(fo == NULL)
        puts("Fisierul energii.out nu s-a putut dechide");
    if(min == 10001)
         fprintf(fo,"%d",-1);
    else
         fprintf(fo,"%d",min);
    fclose(f);
    fclose(fo);
    return 0;
}