function Main(arg) {
    var arg = arg.trim().split('\n');
    var n = Number(arg[0]);
    var aList = arg[1].split(' ');
    
    if(aList.includes('0')){
    		console.log(0);
    		return;
    }
    var ret = 0;
    for (key in aList) {
    	a = BigInt(aList[key]);
    	if(a > 1000000000000000000){
    		console.log(-1);
    		return;
    	}
    	if (ret == 0){
    		ret = a;
    	} else {
        	ret = ret * a;
        }
        if(ret > 1000000000000000000){
    		console.log(-1);
    		return;
        }
    }
    console.log(ret);
    		return;

}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
