import std.stdio;
import std.string;
import std.conv;
import std.algorithm;

void main() {
    int[] buf = readln.chomp.split.to!(int[]);
    int a = buf[0], b = buf[1];

    if (a + b == 15) {
        writeln("+");
    }
    else if (a * b == 15) {
        writeln("*");
    }
    else {
        writeln("x");
    }
}
