diff --git a/beginner/sum-earnings_david.py b/beginner/sum-earnings_david.py
new file mode 100644
index 0000000..81d1240
--- /dev/null
+++ b/beginner/sum-earnings_david.py
@@ -0,0 +1,19 @@
+def sum_earnings(input):
+    streak_sum = 0
+    try:
+        streak = list(map(int, input.split(',')))
+        for num in streak:
+            if num < 0 and num + streak_sum < 0:
+                streak_sum = 0
+            else:
+                streak_sum += num
+    except ValueError:
+        return 0
+    return streak_sum
+
+assert(sum_earnings('1,3,-2,1,2') == 5)
+assert(sum_earnings('0,7,0,2,-12,3,0,2') == 5)
+assert(sum_earnings('0,0,0,0,0') == 0)
+assert(sum_earnings('qwerty') == 0)
+assert(sum_earnings(',,3,,4') == 0)
+assert(sum_earnings('1,2,v,b,3') == 0)
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