In the circuit shown, the input voltage $\mathrm{V}_{\text {in }}=100 ~ \mathrm{mV}$. The switch and the opamp are ideal. At time $\mathrm{t}=0$, the initial charge stored in the $10 ~ \mathrm{nF}$ capacitor is $1 ~ \mathrm{nC}$, with the polarity as indicated in the figure. The switch $\mathrm{S}$ is controlled using a $1 ~ \mathrm{kHz}$ squarewave voltage signal $\mathrm{V}_{\mathrm{s}}$ as shown. Whenever $\mathrm{V}_{\mathrm{s}}$ is 'High', $\mathrm{S}$ is in position '$1$' and when $\text{V}_\text{s}$ is 'Low', $\text{S}$ is in position '$2$'.
At $t=20 \mathrm{~ms}$, the magnitude of the voltage $\mathrm{V}_{\mathrm{o}}$ will be______________$\mathrm{mV}$ (rounded off to the nearest integer).
