import std.stdio, std.algorithm, std.string, std.conv, std.array, std.range, std.math;
int read() { return readln.chomp.to!int; }
int[] reads() { return readln.split.to!(int[]); }


void main() {
    auto a = reads();
    if (a[0] + a[1] == 15)
        writeln("+");
    else if (a[0] * a[1] == 15)
        writeln("*");
    else
        writeln("x");
}
