void solve(){
}
void main(){
	int[] val = inary();
	( (val[0]-1)*(val[1]-1) ).writeln();
}
     
import std.stdio, std.conv, std.algorithm, std.numeric, std.string, std.math, std.range;
const long mod = 10^^9+7;
alias instr = () => readln().chomp();
T inelm(T= int)(){ return to!(T)( readln().chomp() ); }
T[] inary(T = int)(){ return readln().chomp().split().to!(T[])(); }

