Oblate deformation in $^{118,119}$Ag

High spin level schemes of $^{118,119}$Ag are established for the first time by analyzing the high statistics $\gamma$-$\gamma$-$\gamma$ and $\gamma$-$\gamma$-$\gamma$-$\gamma$ coincidence data from the spontaneous fission of $^{252}$Cf at Gammasphere. Two bands with 12 new levels in $^{118}$Ag and two bands with 13 new levels in $^{119}$Ag have been identified. Spins and parities are tentatively assigned according to the systematics. A total Routhian surface calculation and projected shell model calculation have been performed to understand the behavior of these two nuclei. The calculations indicate oblate shape in $^{118,119}$Ag. The dramatic change of signature inversion point in $^{118}$Ag among odd-odd Ag nuclei needs further theoretical consideration.