I agree with Sarah. At any rate, it's unclear whether column P has numeric values or strings; perhaps you'll need
=sumif(p$4: p$39, 1, c$4:c$39)
+sumif(p$4: p$39, 1, d$4:d$39)
+sumif(p$4: p$39, 1, e$4:e$39)
+sumif(p$4: p$39, 1, f$4:f$39)
+sumif(p$4: p$39, 1, g$4:g$39)
+sumif(p$4: p$39, 1, h$4:h$39)
+sumif(p$4: p$39, 1, i$4:i$39)
+sumif(p$4: p$39, 1, j$4:j$39)
+sumif(p$4: p$39, 1, k$4:k$39)
+sumif(p$4: p$39, 1, l$4:l$39)
+sumif(p$4: p$39, 1, m$4:m$39)
+sumif(p$4: p$39, 1, n$4:n$39)
+sumif(p$4: p$39, 1, o$4: O$39)

I'm unclear how to selectively suppress emoticons, but the left side of each above is : and P without a space and the last item on the right is : and O with no space