function Main(input) {
	input = input.split(' ');
        var K=parseInt(input[0]);
        var A=parseInt(input[1]);
        var B=parseInt(input[2]);
        var D=B-A;
        var E=K-A;
        var biscuit=0;
if((E<2)||(D<3)){
  biscuit=K+1;
}else if((E+1)%2===1){
  biscuit=(A+E*D/2+1);
}else{
  biscuit=(A+(E+1)*D/2);
}

console.log(biscuit);
}

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