'commit'

TangDou/LuoGuBook/P1720_0.cpp

@@ -0,0 +1,17 @@
+#include <bits/stdc++.h>
+//十年OI一场空，不开long long见祖宗~
+using namespace std;
+typedef long long LL;
+
+int main() {
+    int n;
+    cin >> n;
+    LL a = 1, b = 1, c = 0;
+    for (int i = 3; i <= n; i++) {
+        c = a + b;
+        a = b;
+        b = c;
+    }
+    cout << c << ".00" << endl;
+    return 0;
+}