string

#include <stdio.h>
#include<string.h>
#include<math.h>

#define maxn 1000

int max ( int a , int b ){
    if ( a > b ) return a ;
    return b ;
}

int main()
{
    int row, col ;
    scanf("%d",&row) ;
    scanf("%d",&col) ;

    char a='a';
    char start = a+max(row,col)-1;
    char temp[maxn]="";
    for (int i=1;i<=row;i++){
        char thisLine[maxn];
        for (int j=0;j<i-1;j++){
            thisLine[j]=temp[j];
        }
        for (int j=i;j<=col;j++){
            thisLine[j-1]=start ;
        }
        for (int j=0;j<strlen(thisLine);j++){
            temp[j]=thisLine[j];
        }
        printf("%s",thisLine);
        printf("\n");
        start--;
    }
    return 0;
}