function Main(input){
    const arr = input.trim().split("\n");
    const AV = arr[0].split(" ").map(Number);
    const BW = arr[1].split(" ").map(Number);
    const T  = Number(arr[2]);
    if(AV[0] + AV[1] * T > BW[0] + BW[1] * T ){
        console.log("YES");
    } else{
        console.log("NO");
    }
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
