diff --git a/S2OJ/183/183.cpp b/S2OJ/183/183.cpp
new file mode 100644
index 00000000..3fd95100
--- /dev/null
+++ b/S2OJ/183/183.cpp
@@ -0,0 +1,50 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, a[110], i;
+bool t1, t2;
+long long l = 0, r = 1000000000, mid, t[110], top;
+
+bool check(long long x) {
+    top = 0;
+    for (i = 1; i < n; i++) {
+        if (a[i] == -1) {
+            t[++top] = x;
+        }
+        else if (a[i] > 0) {
+            t[++top] = a[i];
+        }
+        else if (top > 1) {
+            t[top - 1] += t[top];
+            top--;
+        }
+    }
+    return t[top] <= a[n];
+}
+
+int main() {
+    while (cin >> a[++n]) {}
+    n--;
+    t1 = check(0);
+    if (t[top] == a[n]) {
+        cout << 0 << endl;
+        return 0;
+    }
+    t2 = check(1000000001);
+    if (t1 == t2) {
+        cout << -1 << endl;
+        return 0;
+    }
+    while (l < r) {
+        mid = l + r + 1 >> 1;
+        if (check(mid)) {
+            l = mid;
+        }
+        else {
+            r = mid - 1;
+        }
+    }
+    cout << l << endl;
+    return 0;
+}
\ No newline at end of file