My program crashs when using realloc in c

#include <stdio.h>#include <stdlib.h>char **Names;int size = 2;       //Minimum size for 2D arrayvoid main(){    int i;    Names= (char**)malloc(size*sizeof(char *));      // First initaliaion  of 2D array in heap    for (i = 0; i < size; i++)        Names[i] = (char*)malloc(20*sizeof(char));    printf("\nenter");    for( i=0;i<size;i++)        scanf("%s",Names[i]);    while(1){        size ++;        Names= (char**)realloc(Names,size*sizeof(char *));       //Dynamic allocation of 2D aray        for (i=0; i<size; i++)            Names[i] = (char*)realloc(Names[i],20*sizeof(char));        i =size-1;        printf("\nenter");        scanf("%s",Names[i]);        for( i=0;i<size;i++)            printf("\n%s",Names[i]);    }}

It doesn't crash immediately it depends on the "size" I initialized.It crashes after 5 allocations for me.I tried adding free function but it did not seem to help.