let n = parseInt(readline()); for (let i = 0; i < n; i++) { let arr = readline().split(" ").map(Number); let res = f(arr); console.log(res); } function f(arr) { // 只有当a + p >= b时,才值得让a = a + p let a = arr[0]; let b = arr[1]; let p = arr[2]; let q = arr[3]; let count = 0; while (a < b) { if (a + p >= b) { a = a + p; } else { p = p * q; } count++; } return count; }
var T = parseInt(readline()); while (T--) { var arr = readline().split(" ") var A = parseInt(arr[0]); var B = parseInt(arr[1]); var p = parseInt(arr[2]); var q = parseInt(arr[3]); print(test(A, B, p, q)) } function test(A,B,p,q){ var index = 0; while(A<B){ if(q==1){ A = A+p; }else{ if(A+p<B){ p=p*q; }else{ A=A+p; } } index++; } return index; }