1 files changed, 8 insertions, 8 deletions
diff --git a/src/csharp/Grpc.Examples/proto/math.proto b/src/csharp/Grpc.Examples/proto/math.proto
index 5485d580c3..311e148c02 100644
--- a/src/csharp/Grpc.Examples/proto/math.proto
+++ b/src/csharp/Grpc.Examples/proto/math.proto
@@ -28,30 +28,30 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-syntax = "proto2";
+syntax = "proto3";
 
 package math;
 
 message DivArgs {
-  optional int64 dividend = 1;
-  optional int64 divisor = 2;
+  int64 dividend = 1;
+  int64 divisor = 2;
 }
 
 message DivReply {
-  optional int64 quotient = 1;
-  optional int64 remainder = 2;
+  int64 quotient = 1;
+  int64 remainder = 2;
 }
 
 message FibArgs {
-  optional int64 limit = 1;
+  int64 limit = 1;
 }
 
 message Num {
-  optional int64 num = 1;
+  int64 num = 1;
 }
 
 message FibReply {
-  optional int64 count = 1;
+  int64 count = 1;
 }
 
 service Math {