diff --git a/ACMBR.cpp b/ACMBR.cpp
new file mode 100644
index 0000000..ed6385b
--- /dev/null
+++ b/ACMBR.cpp
@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+using namespace std;
+double dp[102][1003];
+int sp[102][1003],n;
+double solve(int i,int t){
+	if(t==0)return i;
+	if(i==0)return 0;
+	if(sp[i][t]!=-1)return dp[i][t];
+	sp[i][t]=1;
+	double p=(double)i/(double)n;
+	return dp[i][t]=p*solve(i-1,t-1)+(double)(1.0-p)*solve(i,t-1);
+}
+int main() {
+	int t;
+	cin>>t;
+	while(t--){
+	int p;
+	cin>>n>>p;
+	memset(sp,-1,sizeof sp);
+	printf("%.6f\n",solve(n,p));
+	}
+	return 0;
+}
\ No newline at end of file